Polycarbonate resin films, due to their many advantageous properties, are used in many industrial and commercial applications. Polycarbonate resin films, such as for example those derived from 2,2-bis(4-hydroxyphenyl)propane and phosgene, exhibit excellent optical clarity, high dimensional stability, excellent color, high heat resistance, and a high resistance to oxidative degradation.
However, polycarbonate films possess a very high film-to-film kinetic coefficient of friction. This makes handling of polycarbonate films difficult and restricts the use of such films in automatic processing equipment, such as for example packaging equipment, where successful operations necessitate kinetic coefficients of film friction considerably lower than those exhibited by conventional polycarbonate resin films. One effort to produce polycarbonate resin compositions which provide a self-sustaining film exhibiting a commercially acceptable coefficient of friction is described in U.S. Pat. No. 3,424,703. This patent describes a polycarbonate composition containing a polycarbonate resin having intimately dispersed therein a particular modifier which may be either silica or talc and which has an average diameter of up to about 10 microns and which is present in an amount of from about 0.025 to about 0.50 weight percent.
It has been surprisingly discovered that a modifier comprised of glass particles and certain critical amounts of a fatty acid results in polycarbonate resin films which exhibit quite low kinetic coefficients of friction.